Calculate line and phase current, reverse real power or line voltage, and distinguish single-phase, three-phase wye, and three-phase delta quantities.
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- Line to Phase Current Calculator
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Current Per Phase Formula
Use the three modes to find line current, real output power, or required line voltage. For balanced three-phase, Pout = √3 × Vline × Iline × PF × efficiency. Single-phase uses Pout = V × I × PF × efficiency. Efficiency is entered as a percentage and divided by 100; 100% treats output as electrical input power.
k = √3 for balanced three-phase or 1 for single-phase. Voltage is line-to-line for three-phase. Output is in watts in the equation; input controls convert kW and mechanical horsepower. Real electrical input = Pout / η.
Wye/star: Iphase = Iline and Vphase = Vline/√3. Delta: Iphase = Iline/√3 and Vphase = Vline. The phase quantity refers to the load branch or winding. The calculator does not divide a sum of line currents by a phase count.
Typical 3-Phase Voltage and Power Factor Values
These are illustrative system and load examples, not substitutes for equipment nameplate data or measurements. Enter the actual voltage, power factor and efficiency for the operating condition.
| System or region type | Common line-to-line voltage | Notes |
|---|---|---|
| Small commercial 3-phase | 208 V | Common in North American commercial buildings |
| Industrial or commercial | 400 V or 415 V | Common in many IEC-based electrical systems |
| Industrial 3-phase | 480 V | Common for motors, drives, and building equipment |
| Large industrial | 600 V | Used in some industrial distribution systems |
| Load type | Illustrative power factor | Use when |
|---|---|---|
| Resistive load | 1.00 | Heaters or mostly resistive equipment |
| Modern drive or corrected load | 0.95 | VFDs, corrected equipment, or efficient systems |
| Mixed load | 0.85 | Illustration only; measure the actual operating power factor |
| Motor load | 0.80 | Illustration only; motor power factor varies with load |
Current Per Phase Examples
Example 1: Find current per phase from 3-phase power
Use 50 kW output, 400 V line-to-line, power factor 0.85 and 100% efficiency for this illustrative balanced wye/star calculation.
The line current is about 84.9 A. In wye, the phase current is also 84.9 A; in delta, the phase current would be about 49.02 A for the same power, voltage, power factor and efficiency.
Example 2: Single-phase output power
At 240 V, 10 A line current, 0.8 power factor and 100% efficiency, Pout = 240 × 10 × 0.8 = 1.92 kW. At 90% efficiency, the corresponding output would be 1.728 kW while electrical input remains 1.92 kW.
Current Per Phase FAQ
Is current per phase the same as line current?
It depends on the connection. In balanced wye/star, phase current equals line current. In balanced delta, phase current is line current divided by √3. This calculator assumes a balanced load and does not analyze an unbalanced system.
Why does power factor change the current?
Power factor shows how effectively the electrical power is being used. A lower power factor means more current is needed to deliver the same real power. For example, a 50 kW load at 0.80 power factor draws more current than a 50 kW load at 0.95 power factor on the same voltage.
Can you use this for single-phase current?
Yes. Choose Single-phase. Current is Pout / (V × PF × efficiency). The output-power and voltage inverses use the same relationship. There is no split-total-current mode.
